Why is psychology a science?

"Science" involves using the scientific method:

Testable (falsifiable) hypotheses and theories (hence Methods and techniques in psychology: precise operational definitions of phenomena). Empirically-obtained, publicly-available and replicable data (hence usually quantitative measurements). Identification of causal relationships. Parsimony ("Occam's razor"). Healthy scepticism.

Objectives of science: Description, Explanation, Prediction.

Science versus pseudoscience: Objectivity: the need for operational definitions: Many psychological phenomena are poorly defined and/or have "folk Science: Pseudoscience: psychology" definitions: e.g. play, aggression, anxiety, arousal, fatigue, frustration, Evidence-based Based on appeals to authority, intelligence. e.g. "wisdom of the ancients" Operational definitions are in terms of the processes needed to Claims open to scrutiny and Adherents protect claims from measure the phenomenon. refutable disproof All evidence is considered,for and Only apparently-corroborative e.g. "social play" = "wrestling behaviour between two young animals, against claims evidence is considered accompanied by 'play signals' (exaggerated gait, inhibited biting) and unaccompanied by deliberate infliction of injury by either participant". Observable, replicable Phenomena often unreplicable phenomena Scepticism encouraged Scepticism discouraged Game of Scrabble, Mmm, don’t old chap? mind if I do, Parsimonious, and consistent Non-parsimonious, often old bean! with existing science inconsistent with existing science Develops over time Static

1 Definition of autism: DSM IV: DIAGNOSTIC CRITERIA FOR AUTISTIC DISORDER Objectivity: the need for precise measurement: A. A total of six (or more) items from (1), (2), and (3), with at least two from (1), and one each from (2) and (3) 1. Qualitative impairment in social interaction, as manifested by at least two of the following: a) marked impairments in the use of multiple nonverbal behaviors such as eye-to-eye gaze, facial expression, body posture, and gestures to regulate social interaction. Independent variable - the thing you manipulate, as an b) failure to develop peer relationships appropriate to developmental level. c) a lack of spontaneous seeking to share enjoyment, interests, or achievements with other people, experimenter. (e.g., by a lack of showing, bringing, or pointing out objects of interest to other people). Dependent variable - the thing you measure. d) lack of social or emotional reciprocity (e.g. not actively participating in simple social play or games, preferring solitary activities, or involving others in activities only as tools or "mechanical" aids). e.g.: effects of status on initial interaction distance (Dean, Willis and 2. Qualitative impairments in communication as manifested by at least one of the following: a) delay in, or total lack of, the development of spoken language (unaccompanied by an attempt to Hewitt 1975) compensate through alternative modes of communication such as gesture or mime). b) in individuals with adequate speech, marked impairment in the ability to initiate or sustain a conversation with others. c) stereotyped and repetitive use of language or idiosyncratic language. IV: status - operational definition: military rank d) lack of varied, spontaneous make-believe play or social imitative play appropriate to developmental level. DV: interaction distance - operational defnition: number of floor squares between interactors (various settings, all with standard 3. Restricted repetitive and stereotyped patterns of behavior, interests and activities, as manifested by at least two of the following: floor-tile size) a) encompassing preoccupation with one or more stereotyped and restricted patterns of interest that is abnormal either in intensity or focus. b) apparently inflexible adherence to specific, nonfunctional routines or rituals. Inter-observer reliability checked c) stereotyped and repetitive motor mannerisms (e.g hand or finger flapping or twisting, or complex whole- body movements). d) persistent preoccupation with parts of objects. Results: status affected interpersonal distance: initial distance was B. Delays or abnormal functioning in at least one of the following areas, with onset prior to age 3 years: higher when a lower-rank person approached a higher-rank person, (1) social interaction. than when peers met or a higher-rank person approached a lower- (2) language as used in social communication. (3) symbolic or imaginative play. rank person

C. The disturbance is not better accounted for by Rett's Disorder or Childhood Disintegrative Disorder.

Objectivity: the need to avoid experimenter Theories and data: effects: Theories integrate and summarise scientific facts. Give rise to hypotheses - specific predictions. Interaction between theory and observation: Huge literature on how experimenters can bias results theory guides observation, observation modifies theory (Rosenthal 1966). mental activity affects brain health theory Ways to minimise these effects: listening to Beyoncé rots hypothesis your brain

(a) study Beyoncé fans, or Precise definitions of IV's and DV's. test (observation, experiment) (b) experiment - listeners vs Standardised instructions and procedures. revise theory non-listeners Double-blind techniques. hypothesis only long periods of exposure Independent replication. have ill-effects

test (observation, experiment) prolonged mental activity affects brain health

2 History of psychology: History of neuropsychology:

19th c.: introspective methods - results open to 19th c.: detailed qualitative single-patient case studies. dispute. Problem - results open to different interpretations.

Early 20th c.: Behaviourism - restriction to purely Early 20th c.: quantitative group studies. behavioural measures that are amenable to Problem - group performance does not necessarily quantitative analysis. reflect individual performance.

Late 20th c.: behavioural data used as an indirect Late 20th c.: detailed quantitative single-patient case measure of unobservable internal states (e.g. RT as an studies. Descriptions of patients supported by index of processing speed in cognitive psychology). quantitative data (plus statistical comparisons of patient to group norms).

Tinbergen (1963): four "whys": Methods used in psychology:

Ultimate and proximate causes of behaviour. Advantages Disadvantages

1. Function (adaptation: ultimate cause) 2. Causation (proximate cause) Observation Naturalistic Time-consuming. Unlikely to 3. Ontogeny (development: proximate cause) behaviour. reveal causal relationships. 4. Phylogeny (evolutionary history: ultimate cause) Interviews, Case In-depth, Reporting bias. Studies and detailed Lack of self-insight. e.g. Why do starlings sing? (1) To attract mates to breed. (2) information. Increasing day-length affects hormone levels. (3) They learn to Questionnaires sing from their neighbours. (4) Song has evolved from simpler Experiments Best way to Data sometimes too closely songs in ancestral bird species. establish causal tied to theory. relationships Artificial (ecological validity) Psychology has traditionally focused on 2 and 3, neglecting 1 Participant representativeness. and 4.

3 is it safe to use a mobile phone while driving?: Advantages Disadvantages Problems with correlational techniques:

Observation Information Accidents involving Does smoking cause cancer? (accident on real- phones are rare (Violanti statistics) world risks. 1998: 5 users out of sample of 223,137 Strong correlation between smoking and cancer -but accidents ! does smoking cause cancer? Interviews, In-depth, Reporting bias (Chapman Case Studies detailed and Underwood 2000: Alternative explanations: and information. 80% of near-accidents Cancer-prone people are attracted to smoking. Questionnaires forgotten within 2 weeks). Experiments Best way to Simulators cannot Stress causes people to smoke and to develop cancer. establish simulate real risks of how phone- driving; real-world studies use might are unethical. Correlations usually have too many alternative increase Artificial tasks, in terms of explanations. risk of content and timing of accident. conversation. Participants often unrepresentative.

The "Mozart Effect": babies that listen to Mozart before The experimental method is the best way of identifying birth are supposedly more intelligent as children. causal relationships.

X (listening to Mozart) is associated with Y (intelligence). X causes Y if:

What causes the change in intelligence? X occurs before Y To demonstrate a causal relationship, need to show that Y happens in the presence of X (a) listening to Mozart precedes the change in Y does not happen in the absence of X intelligence (X precedes Y); (b) the change in intelligence occurs when babies listen to Mozart (Y happens in presence of X); (c) the change in intelligence does not occur when babies do not listen to Mozart (Y does not happen without X: i.e. other explanations can be ruled out).

4 Alternative explanations for the Mozart effect: Good experimental designs enable us to eliminate some 1. Listening to Mozart directly affects intellligence by of these alternative explanations: stimulating neural development. To establish causality we use groups that differ 2. Babies who listen to Mozart have better - educated systematically only on one variable (the independent parents (more interested in their children's development variable) and measure the effects of this on an outcome and education). variable (the dependent variable).

3. Babies who listen to Mozart have better - educated Pick pregnant women who do not Randomly assign half to listen parents (wealthier and therefore healthier). differ systematically on any variables (age, musical to Mozart, and half to listening preferences, SES, health, etc.). to something else. 3. Mothers who listen to Mozart are more relaxed; somehow this affects the baby's neural development.

4. Babies who listen to Mozart are more relaxed; Measure the children's intelligence: systematic differences between groups are probably due to the somehow this affects their neural development. mothers' different experiences (i.e. Mozart/ no Mozart).

Experiment to test the Mozart effect: Why do we use statistics?

Most studies compare groups - Behaviour often shows variability: hence individual performance may be atypical. Individuals in a group vary randomly around "average" performance. Compare average of one group to average of another.

The ONLY systematic variation between experimental and control groups is exposure to Mozart: worrying, happiness, motivation, irritability, etc. vary randomly (unsystematically) between groups

5 Why do we use statistics? The kinetic depth effect Exceptions - Behaviourist studies. Psychophysical studies. High degree of control over behaviour reduces variability and enhances replicability of findings.

Typical patterns of lever- pressing in response to different schedules of reinforcement Effects of frame-to-frame distance between dots on perception of depth

Disadvantages of the experimental method: Conclusion:

Intrusive - participants know they are being observed, Experiments are a useful tool for establishing cause and and this may affect their behaviour. effect - but other methods (e.g. observation) are also important in science. Experimenter effects. A good experimental design ensures that the only Not all phenomena are amenable to experimentation, for variable that varies is the independent variable chosen practical or ethical reasons (e.g. post-traumatic stress by the experimenter - the effects of alternative disorder, near-death experiences, effects of physical and confounding variables are eliminated (or at least social deprivation, etc.) rendered unsystematic by randomisation).

Some phenomena (e.g. personality, age or sex "Science" is mainly defined not by what you study, but differences) can only be investigated by methods which by how you study it. are, strictly speaking, quasi-experimental.

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